X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=src%2Ftim%2Fprune%2Fsave%2Fxml%2FXmlUtils.java;fp=src%2Ftim%2Fprune%2Fsave%2Fxml%2FXmlUtils.java;h=643ebb015c5d8aa6a0e1dd1c3bb754ddb355fd11;hp=0000000000000000000000000000000000000000;hb=ce6f2161b8596f7018d6a76bff79bc9e571f35fd;hpb=2d8cb72e84d5cc1089ce77baf1e34ea3ea2f8465

diff --git a/src/tim/prune/save/xml/XmlUtils.java b/src/tim/prune/save/xml/XmlUtils.java
new file mode 100644
index 0000000..643ebb0
--- /dev/null
+++ b/src/tim/prune/save/xml/XmlUtils.java
@@ -0,0 +1,129 @@
+package tim.prune.save.xml;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.nio.charset.Charset;
+
+/**
+ * Collection of utility functions for handling XML
+ */
+public abstract class XmlUtils
+{
+	/** Start of Cdata sequence */
+	private static final String CDATA_START = "<![CDATA[";
+	/** End of Cdata sequence */
+	private static final String CDATA_END = "]]>";
+	/** Cached copy of system encoding string */
+	private static String _systemEncoding = null;
+
+	/**
+	 * Fix the CDATA blocks in the given String to give valid xml
+	 * @param inString String to modify
+	 * @return fixed String
+	 */
+	public static String fixCdata(String inString)
+	{
+		if (inString == null || inString.isEmpty()) return "";
+		if (!hasIllegalCharacter(inString)) {
+			return inString;
+		}
+		String result = inString;
+		// Remove cdata block at start if present
+		if (result.startsWith(CDATA_START)) {
+			result = result.substring(CDATA_START.length());
+		}
+		// Remove all instances of end block
+		result = result.replaceAll(CDATA_END, "");
+		// Now check whether cdata block is required
+		if (!hasIllegalCharacter(result)) {
+			return result;
+		}
+		return CDATA_START + result + CDATA_END;
+	}
+
+	/**
+	 * Checks the input string for the three illegal characters,
+	 * but only looping through the string once instead of three times
+	 * @param inValue string to check
+	 * @return true if at least one of the illegal characters is found
+	 */
+	public static boolean hasIllegalCharacter(String inValue)
+	{
+		if (inValue == null) return false;
+		final int numChars = inValue.length();
+		for (int i=0; i<numChars; i++)
+		{
+			final char c = inValue.charAt(i);
+			if (c == '<' || c == '>' || c == '&')
+			{
+				return true;
+			}
+		}
+		return false;
+	}
+
+	/**
+	 * @return true if system uses UTF-8 by default
+	 */
+	public static boolean isSystemUtf8()
+	{
+		String systemEncoding = getSystemEncoding();
+		return (systemEncoding != null && systemEncoding.toUpperCase().equals("UTF-8"));
+	}
+
+	/**
+	 * @return name of the system's character encoding
+	 */
+	public static String getSystemEncoding()
+	{
+		if (_systemEncoding == null) {
+			_systemEncoding = determineSystemEncoding();
+		}
+		return _systemEncoding;
+	}
+
+	/**
+	 * Use a temporary file to obtain the name of the default system encoding
+	 * @return name of default system encoding, or null if write failed
+	 */
+	private static String determineSystemEncoding()
+	{
+		File tempFile = null;
+		String encoding = null;
+		try
+		{
+			tempFile = File.createTempFile("gpsprune", null);
+			OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(tempFile));
+			encoding = getEncoding(writer);
+			writer.close();
+		}
+		catch (IOException e) {} // value stays null
+		// Delete temp file
+		if (tempFile != null && tempFile.exists()) {
+			if (!tempFile.delete()) {
+				System.err.println("Cannot delete temp file: " + tempFile.getAbsolutePath());
+			}
+		}
+		// If writing failed (eg permissions) then just ask system for default
+		if (encoding == null) encoding = Charset.defaultCharset().name();
+		return encoding;
+	}
+
+
+	/**
+	 * Get the default system encoding using a writer
+	 * @param inWriter writer object
+	 * @return string defining encoding
+	 */
+	public static String getEncoding(OutputStreamWriter inWriter)
+	{
+		String encoding = inWriter.getEncoding();
+		try {
+			encoding =  Charset.forName(encoding).name();
+		}
+		catch (Exception e) {} // ignore failure to find encoding
+		return encoding;
+	}
+}